A sidewall mask process (or a double patterning process) is known as a semiconductor process technology. This process is characterized in that a pattern smaller than a minimum processing size by photolithography can be formed. According to the process, even if the photolithography size is reduced, variations in width of processed patterns do not arise and thus, the process is promising, for example, for processing of an active area and a gate electrode in which a miniaturization is conspicuous. However, according to the sidewall mask process, patterns having different widths cannot be formed in parallel.